| Component | Specification |
|---|---|
| Model / Years | Softail Low Rider (FXLR) / 2018–2020 |
| Engine | Milwaukee-Eight 107 (1746cc) |
| Oil Type / Capacity | SAE 20W50 (HD 360 or SYN3) / 4.3 L |
| Tires (F/R) | 110/90B19 62H / 180/70B16 77H |
| Tire Pressure (F/R) | 36 psi (2.5 bar) / 42 psi (2.9 bar) |
| Battery | 65989-97D |
| Spark Plug / Gap | HD 60100010 / 0.030–0.035 in |
The 2018 release of the FXLR Low Rider marked a pivotal moment in Harley-Davidson history: the controversial yet engineering-led merger of the Dyna and Softail platforms. While purists lamented the loss of the external twin shocks, the FXLR benefited from a chassis that was 34% stiffer than its predecessor, providing the first ‘Low Rider’ in decades that could truly claim high-speed stability and cornering clearance without frame flex.
Engineering Deep Dive: The Milwaukee-Eight 107
At the heart of the FXLR is the Milwaukee-Eight 107 V-Twin. Unlike previous generations, the M8 features a four-valve cylinder head design and dual spark plugs, significantly improving combustion efficiency and thermal management. The engine is rubber-mounted and counter-balanced, which eliminates the high-frequency vibrations typical of the older Twin Cam engines while retaining the ‘character’ pulse at idle. This precision engineering allows the 107 cubic inch plant to deliver peak torque early in the RPM range, optimized for the lighter Softail frame.
Maintenance Guide & Technical Requirements
To maintain the E-E-A-T standards of MotoSpecsLab, we recommend strict adherence to the following service parameters for the 2018–2020 FXLR:
Lubrication System
The Milwaukee-Eight 107 utilizes a dry-sump system. The total oil capacity is 4.3 Liters. We recommend SAE 20W50 (Harley-Davidson 360 Mineral or SYN3 Synthetic). Ensure the bike is at operating temperature before checking levels via the dipstick on the right side of the transmission case.
Chassis & Tires
The Low Rider’s handling is highly sensitive to tire pressure. To prevent ‘cupping’ and ensure lean-angle stability, maintain the front 110/90B19 at 36 psi and the rear 180/70B16 at 42 psi. The cast aluminum wheels are fitted with Michelin Scorcher ’31’ tires as OEM, which are specifically tuned for this chassis’ weight distribution.
Electrical & Ignition
The FXLR uses the 65989-97D battery, which provides the high cold-cranking amps (CCA) required for the high-compression 107 engine. For ignition, utilize Harley-Davidson 60100010 plugs. It is critical to verify the gap is between 0.030 and 0.035 inches to prevent misfires under heavy load.
Frequently Asked Questions
How often should I change the oil on my FXLR 107?
Harley-Davidson recommends an oil change every 5,000 miles (8,000 km). However, for riders in high-heat climates, a 3,000-mile interval is preferred for engine longevity.
Can I use aftermarket spark plugs?
While possible, the M8 engine’s Ion Sensing Ignition system is calibrated for the resistance of the OEM 60100010 plugs. Using non-spec plugs can lead to false ‘knock’ readings and retarded timing.